I'm trying to emerge aufs3 with the kernel patch on a system using gentoo-sources-3.4.9. The emerge succeeds but there are unknown "symbol errors" reported and these prevent the aufs.ko module from loading:

Edit: It worked! The missing symbol errors went away. I got a different fatal error when I tried to "modprobe aufs" but that error went away when I emerged aufs3 again after rebuilding and installing the kernel after emerging aufs3 for the first time.